Doctors late Monday agreed to run one more series of tests to determine if there is any brain activity coming from Jahi McMath. Earlier in the day, doctors planned to take her off life-support after she was declared brain dead on Dec. 12. George Kiriyama reports. (Published Tuesday, Dec 17, 2013)

The family of an Oakland 13-year-old girl is demanding answers after a routine procedure to help fix her sleep apnea turned tragic when she was declared brain dead three days after having her tonsils removed.

Doctors late Monday agreed to run one more series of tests to determine if there is any brain activity coming from Jahi McMath. Earlier in the day, doctors planned to take her off life support after she was declared brain dead on Dec. 12.

Jahi's family has also reached out to Oakland Mayor Jean Quan to see if she can help delay the hospital from taking the girl off life support.

The eighth-grader went into the hospital on Dec. 9 for what her family expected to be a routine surgery. Moments after waking up from a tonsillectomy, Jahi was talking with her family and asking for a popsicle. Thirty minutes later, she was choking on her own blood and going into cardiac arrest in the Oakland Children's Hospital's Intensive Care Unit, according to her relatives.

On Monday morning, Jahi's mother, stepfather uncle and grandmother met again with doctors to demand that the hospital conduct an investigation into what happened to the E.C. Reems Academy of Technology and Arts student known for her bubbly spirit and wide-tooth grin.

Monday afternoon, doctors told the family that Jahi is considered legally dead. Dr. David Durand, the head of pediatrics, told the family that they will take Jahi off life support Tuesday, though the girl's family said earlier they were vehemently against that.

Durand said the hospital can't disclose the details of Jahi's case because her family asked it not to disclose them to the media.

Under California law, “A person who is declared brain dead is legally and physiologically dead.”

Jahi’s family says they can’t believe they have no rights. They say they want to keep Jahi on life support. They’re even willing to take her to another hospital or a nursing home, but in accordance with the law, the hospital is saying no.

"It's not even up to us to even keep her on life support, because she's been legally dead," said Omari Sealey, Jahi's uncle. "It's so hard for my family. It's so hard for me."

Sealey said the family believes an error was committed by the hospital, either before, during, or after surgery. "I absolutely believe that somewhere along the way, there was a protocol that wasn’t followed, or there was a surgical error.”

"My child was fine before I brought her here," Jahi's mother, Nailah Winkfield, said outside the hospital Monday morning. "I don't want to bury my 13-year-old, who came here for a better quality of life. This is horrible. I will not leave without my daughter. This is a mother's worst nightmare."

A spokeswoman for the hospital said staff is "currently reviewing the case and we do not have enough information to make any further statements at this time."

“We are very sad about her condition and our hearts go out to her family," spokeswoman Melinda Krigel said in an email.

Sealey provided a rough timeline of what happened after Jahi's tonsils were removed a week ago. After she asked for a popsicle, it became immediately clear that something was wrong.

“She wasn’t able to talk, and she started to write notes to her mother, saying, 'I’m swallowing too much mucus, Mom – am I OK? Mom – I feel like I’m choking,'” Sealey recalled. “And she began to write these notes because she couldn’t talk because there was so much blood. It wasn’t mucus – it was blood. But my sister, the mother, was too afraid to let her know that it was blood and not mucus," Sealey said.

He said the scene was gruesome. “She was coughing up buckets of blood,” he said.

At the same time, Sealey said it appeared to the family as though the nursing staff had vanished during what seemed to be a shift change. In the family's minds, there didn't seem to be enough hospital staff in the room to help. The family started suctioning blood themselves; Jahi's grandmother, Sandra Chatman, is a nurse at another hospital.

“A 13-year-old should not have to suction herself,” Sealey said. “She had to use a suction machine to suction her own blood. Her mother and stepfather had to suction out her blood at points. None of them work for this hospital.”

The family hasn’t left Jahi’s side since the surgery. They are making sure she is comfortable and playing her favorite songs to her on her iPod.

“My little girl in there, my little niece, is in there with her own heartbeat, which lets me know that she is alive,” Sealey told NBC Bay Area.

“We’ve had a lot of supporters here,” Sealey said. “There’s been lots and lots of prayers, lots of faith, lots of belief. And everyone’s spirits are strong right now. We don’t want them taking her off life support; we are a family of God, and we do honestly believe that she will get up."